Synthetic lubricant



Patented Jan. 9, 1945 UNITED STATES PATENT OFFICE 2,367,133 SYNTHETICLUBRICANT Bert H. Lincoln, Gordon D. Byrkit, and Waldo L. Steiner, PoncaCity, Okla., assignors, by mesne assignments, to Socony-Vacuum OilCompany,

Incorporated, New York,

of New York N. Y., a corporation No Drawing. Application November 27,1940,

' Serial No. 367,461

7 Claims. (Cl. 252-48) the standpoint of oxidation in use, it isnecessary.

to refine the oil thoroughly and then to add an inhibitor of oxidation.3 The thorough refining may consist of more and heavier acid treatmentsor solvent treating so as to remove a considerable part of the oil andleave only the most stable portion. Such drastic refining is necessaryin order to obtain stability with respect to sludge formation, but theoil is .then subject to easy oxidation to form soluble acids and othercorrosive materials. This can be prevented by the addition metallicatoms present in the molecule may be,

to the refined oil of small amounts of materials which either preventthe formation of these corrosive products or by some action render theminert.

Many of these additive materials are effective when added to poorlyrefined or even wholly unrefined lubricants. The addends may thus besubstituted in whole or in part for the usual refining processes.

In the prior art of applying these principles to the manufacture oflubricants, many diverse types of materials have been suggested to beadded to obtain improvement in various characteristics.

It has been found that the addition of various metal-bearing organiccompounds frequently improves film strength, oxidation resistance,noncorrosiveness, and other characteristics. In particular, tin invarious combinations has been found to inhibit the development duringuse of corrosivematerials. Lead compounds, particularly in combinationwith sulfur in some form (e. g., sulfurized oils), are used to improvefilm strength,

I especially in soap-thickened oils, such as greases and the like. Leadcompounds do not in general, however, improve the oxidation andcorrosive characteristics of a lubricant; audit is usuallyconsideredthat lubricants containing lead compounds are unsuited forcrankcaselubricants.

They are usually employed in transmissions, difi ferentials, and thelike where temperatures are relatively low and and no easily corrodedmetals are.present.

One object of our-invention is to provide improved inhibitors ofoxidation and corrosion for addition to lubricants.

- element possesses this characteristic to the extent Another object orour invention s to provide oil-soluble organo-metallic compounds whichcontain relatively high percentages of metal.

A further object-of our invention is toprovide readily.

materials which are efieotive in extremely small aIIlOllhtS.

A still further object of our invention is to provide film-strengthimproving organo-metal-lic compounds suitable for use in lubricants andespecially in crankcase lubricants.

Another object of our invention is-to provide. the possibility ofincluding in one and the same addition agent factors for improving-'film strength, increasing resistance to the formation of oil-soluble(acidic) and oil-insoluble (sludge) oxidation products, and decreasingcorrosiveness developed during use.

Other and further objects of our invention will appear from thefollowing description.

Briefly, our addition agents for accomplishing the above purposes areopen-chain organo-metallic compounds containing more than one metallicatom per molecule but containing no metal-to-metal bonds. None of thevalences of the combined with the valences of another. metal atom. ,Morespecifically, this application discloses the use of open-chainorgano-arsenic compounds so constituted.

Since it is the metallic atom or atOms in the molecule and not theparticular organic radicals present which are responsible for thedesirable functions, it is apparent that the more metal atomspresent inthemolecule, the better. Openchain organo-m-etallic compounds containingmore than one metal atom permolecule are not extremely common; and mostof those known have the plurality of metal atoms combined with eachother in chains, for example, hexamethyl distannane, (CH3); Sn.Sn(CH3)3.' The bonds between the metal atoms in compounds of this type,however, are extremely Weak as compared, for example, with thecarbon-metal bond. "As a result the compounds are relatively unstablechemically, tending to decompose and react While the elements of groupIV of the periodic table of the elements and a very few others, and inparticular tin and lead, have to a very limited extent the ability tocombine with themselves, no

which carbon does. Carbon is par excellence, the element which formschains, clusters, and rings united by stable bonds. Furthermore, whilethe metal-metal bonds are weak, the carbon-metal bonds are quite'strong,which provides greater stabilityf Hence, according to our dnvention, we

use open-chain organo-metal-lic compound containing two ormore atoms ofmetal which may bethe same or different and in which there are nometal-metal bonds.

Itis'to be understood that in practicing our in:

vention, oil-soluble organo-metallic compounds of the type described aretobe selected. Some of the examples described belowhave only limitedsolubility in hydrocarbon'oils. It isto be remembered, however, thatbecause of the high content of metals in our compounds, extremely smallamounts are often effective. Thus we may use as little as 0.001 per centof some of these com- Dounds and it will be seen that a. fairlyinsoluble material may dissolve to a sufficient extent to besatisfactory for our purpose. In general, 0.001 per cent or more of ouraddition agents is used, and we may add one, two or even five per centor more. v

Furthermore, it is well known that different types of oils havedifferent capabilities of dissolving a given material. For somepurposes, therefore, we prefer parafiinic, and for other purposesasphaltlc, naphthenic, or mixed base lubricants. Another method ofobtaining a satisfactory mixture of addition agent with the hydrocarbonoil is the use of a mutual solvent to bring the addend into solution.Alternatively peptizing agents may be added to maintain theorgano-metallic compound in permanent suspension.

Many of the more difllcultly soluble materials are rendered more solubleby the'introduction of alkyl groups, particularly those containing fouror more carbon atoms. The isoamyl, octyl, lauryl, and octadecyl radicalsand radicals from paraflin wax greatly increase the solubility oforganic compounds in oil. One or more of such groupsmay be introduced asrequired.

The following are preferred-examples of our addition agents which aregiven as illustrations and not as limitations:

- 1. 1,5-bisdimethylarsenylpentane, (CH2)5 AS (CH3) 2.

This compound may be prepared by the method disclosed in Beilstein,volume 4, page 606, system number 410, for the preparation of ananalogous compound, namely, 1,2-bis-diarsenyl ethane, HzAs -(CHz)2'ASH2.

2. Diamylarsenic oxide, [(C5H11)2 As]: O.

This compound may be prepared by the pro-- cedure described on page 61of the text Organic Arsenical Compounds," Raiziss and Gavron, AmericanChemical Society Monograph Series, N. Y., 1923.

3. Diamylarsenic sulfide, [(C5H11)2 A512 S.

On page 618 Raiziss and Gavrons text, it is (CH3)2 As shown that thiscompound can be prepared by passing hydrogen sulfide through asuspension of the corresponding chloride, (H11C5)z As C1, in water.

4. Diamylarsenic disulfide, [(C5H11):| As]: S2.

It will apparent to any chemist skilled in the art that the procedurefor the preparation of diisoamyl arsine sulfide can be modified in orderto prepare the corresponding disulfide. That is, the disulfide may beprepared by passing hydrogen sulfide through a suspension of thecorresponding chloride and sulfur in water.

Other methods of preparation of the foregoing preferred compounds willbe apparent from the discussion of such arsenic compounds in A I'extbookof Organic Chemistry, volume xr, page 1, A. E. Goddard and D. Goddard,Friend edition, London, 1928.

It will be apparent from thejoregoing examples that the preferredcompounds of this in-' ventlon contain more than one atom of trivalentarsenic.

It may be desirable to include in one and the same blend based on ahydrocarbon oil, in addition to the addends here described, otheraddends for specific purposes. we may add a -pour point depressor suchas a naphthalene-chlor wax condensation product and a viscosity indeximprover, such as certain resins or polymerized hydrocarbons in additionto our organo-metallic compounds. Furthermore, other metallic compoundsmay be added to the blend without interfering with the action of ouringredients. In-

' deed, in some cases it is advantageous to comeither directly or afterbeing blended first in a lubricating oil and then added to the fuel.Soapthickened mineral oils of all types, ranging from those showing onlya slight increase in viscosity over that of the mineral oil alone, tothe semisolid and solid greases containing fifty per cent or more ofsoap, are amenable to treatment according to our invention.

It will be understood that certain features and sub-combinations are ofutility and may be em-- ployed without reference to other features andsub-combinations. This is contemplated by and is within the scope of ourclaims. It is further obvious that various changes may be made indetails within the scope of our claims without departing from the spiritof. our invention. It is therefore to be understood that our inventionis not to be limited to the specific details shown and described.

Having thus described our invention, we claim:

1. A lubricant comprisin a major proportion of oil of lubricatingviscosity and a minor proportion of an open chain organo-arseniccompound containing more than one metallic atom but no metal-to-metalbonds.

A lubricating comprising a major portion of oil of lubricating viscosityand a minor proportion of an open chain organo-a'rsenic compoundcontaining at least two metallic atoms and no metal-to-metal bonds.

3. A lubricant comprising a major proportion of oil of lubricatingviscosity and a minordproportion of an open chain organo-arseniccompound containing at least two metallic atoms in which all thevalences of the metalic atoms are joined to non-metals.

4. A lubricant comprising a major proportion of oil of lubricatingviscosity and a minor proportion of an open chain organo-arseniccompound containing more than one metallic atom in which all thevalences of the metallic atoms are joined to. carbon.

5. A lubricant comprising oil of lubricating viscosity and from 0.001 to5 per cent of an open chain organo-arsenic compound containing more thanone metallic atom but no metal-to-metal bonds. v Y

6. A lubricant comprising a major proportion of oil of lubricatingviscosity and a minor proportion of diamylarsenic oxide.

7. A lubricant comprising a major proportion of oil of lubricatingviscosity and a minor proportion of diamylarsenic disulfide.

. BERT H. LINCOLN.

GORDON D. BYRKIT. WALDO L. STEINER.

